Change record status: 
Project: 
Introduced in branch: 
11.4.x
Introduced in version: 
11.4.0
Description: 

RegisterForm is adding an undocumented password property on the $account object.
Accessing this property is deprecated and the property will be removed in Drupal 12.

Accessing this property will now trigger a deprecation:

$password = $account->password;
Impacts: 
Module developers